Jellyfish Takeover?

"In simple terms, jellyfish blooms are growing – and stresses caused by human activity such as overfishing are said to be the most likely cause. Fisheries-based ecosystems are frequently overfished, and taking too many fish out of ecosystems creates ecological space for jellyfish to thrive." ~Pew Environment Group

Lead author Lucas Brotz dives with a lion's mane jellyfish (Cyanea capillata) in Indian Arm, British Columbia. Credit: Conor McCracken | Click for source and to learn more

"Over recent decades, man's expanding inﬂuence on the oceans has begun to cause real change and there is reason to think that in some regions, new blooms of jellyﬁsh are occurring in response to some of the cumulative effects of these impacts. The issue is not simple and in most cases there are few data to support our perceptions." ~Marine Biologist Claudia Mills

"Jellyfish are increasing in the majority of the world’s coastal ecosystems. In a study published in the edition of the journal Hydrobiologia, UBC scientists examined data for numerous species of jellyfish for 45 of the world’s 66 Large Marine Ecosystems. They found increasing jellyfish populations in 62 percent of the regions analyzed, including East Asia, the Black Sea, the Mediterranean, the Northeast U.S. Shelf, Hawaii, and Antarctica. There has been anecdotal evidence that jellyfish were on the rise in recent decades, but there hasn’t been a global study that gathered together all the existing data until now. Our study confirms these observations scientifically after analysis of available information from 1950 to the present for more than 138 different jellyfish populations around the world." ~Jellyfish on the rise: UBC study

"Since 2002, the population has exploded — in jelly parlance, bloomed — six times. In 2005, a particularly bad year, the Sea of Japan brimmed with as many as 20 billion of the bobbing bags of blubber, bludgeoning fisheries with 30 billion yen in losses. In recent years, populations of several jellyfish species have made inroads at the expense of their main competitor — fish — in a number of regions, including the Yellow Sea, the Gulf of Mexico, and the Black Sea. Overfishing and deteriorating coastal water quality are chief suspects in the rise of jellies. Global warming may be adding fuel to the fire by making more food available to jellyfish and opening up new habitat. Now, researchers fear, conditions are becoming so bad that some ecosystems could be approaching a tipping point in which jellyfish supplant fish." ~Richard Stone, Yale Environment 360, Massive Outbreak of Jellyfish Could Spell Trouble for Fisheries